Recently, high speed operation has been required for semiconductor integrated circuit devices. Speedup of the operation is mainly towed by the miniaturization of semiconductor devices such as transistors or the like, the reduction in wiring resistance, the reduction in dielectric constant of interlayer insulating films, and the like. However, the speedup of operation by these techniques has reached its limits.
Therefore, in order to further speed up the operation, germanium (Ge) or silicon germanium (SiGe), which is a semiconductor material having higher carrier mobility, is used in place of silicon (Si) which is a conventionally used semiconductor material. The application of germanium (Ge) or silicon germanium (SiGe) to a channel portion material of a transistor has been studied.
Incidentally, a high dielectric constant film (High-k film) is frequently used as a gate insulating film on a channel portion made of Ge or SiGe in response to miniaturization. There is a need for a high quality film with few impurities. Therefore, it is sometimes required to form a high-k film at a temperature exceeding 450 degrees C., particularly at a high temperature of 500 to 600 degrees C.
However, after the substrate having a Ge film or a SiGe film on its surface is loaded into a processing container from an air atmosphere and is heated to a temperature exceeding 450 degrees C., the Ge film or the SiGe film is etched and there is a high amount of deterioration of the surface of the substrate. For this reason, the film is formed at a temperature lower than the original temperature, or a special method such as flash lamp annealing or the like is used in which only the outermost surface is affected by temperature.